A common question during the quoting process is whether or not the total number of drills can affect the PCB fabrication cost. With Bittele Electronics, the simple answer to this question would be no. To offer our clients the lowest possible pricing, Bittele Electronics does not charge on a per hole basis, but rather only charges for special requirements such as castellated holes, blind holes, controlled depth drilling, etc. There are, however, many other factors when considering drill holes that can affects the lead time, such as the number of different hole sizes and the actual hole size itself.
The number one reason why the number of drill holes will affect your PCB fabrication lead time is simply the amount of time and effort that it will take to finish fabricating that PCB. Generally, for prototyping and smaller orders, the number of drills will not affect your lead time, however, this may change for much larger production orders. At Bittele Electronics, all holes are drilled using numerical control (NC) drilling machines.
The number of different size drill holes can have a significant affect on your PCB fabrication time. With many different drill holes sizes, we are required to re-tool the drilling machinery, typically in the time it takes to perform a tool change, roughly 200 holes could have been drilled. We recommend limiting the number of unique hole sizes where possible. Selecting a happy medium between two desired hole sizes will help reduce the fabrication time. Boards that require laser drilling can also be costlier to fabricate. More information about this can be found here.